package gqz.mvvm.view.custom;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.CornerPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.support.annotation.Nullable;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.List;

import gqz.mvvm.R;

/**
 * Created by Administrator on 2017/12/5.
 */

public class ViewPagerIndicator extends LinearLayout {

    private final String TAG = "ViewPagerIndicator---";
    //绘制指示器的画笔
    private Paint mPaint;
    //构成指示器形状的路径(三角形指示器)
    private Path mPath;
    //指示器的宽高
    private int mTriangleWidth, mTriangleHeight;
    //屏幕宽度
    private int screenW = 0;
    //指示器的宽度为单个Tab的1/6
    private static final float RADIO_TRIANGEL = 1.0f / 6;
    //三角形的最大宽度
    private final int DIMENSION_TRIANGEL_WIDTH = (int) (getScreenWidth() / 3 * RADIO_TRIANGEL);
    //初始时，三角形指示器的偏移量
    private int mInitTranslationX;
    //手指滑动时的偏移量
    private float mTranslationX;
    // 默认的Tab数量
    private static final int COUNT_DEFAULT_TAB = 4;
    // tab数量
    private int mTabVisibleCount = COUNT_DEFAULT_TAB;
    // tab上的内容
    private List<String> mTabTitles;
    // 与之绑定的ViewPager
    public ViewPager mViewPager;
    // 标题正常时的颜色
    private static final int COLOR_TEXT_NORMAL = 0x77FFFFFF;
    // 标题选中时的颜色
    private static final int COLOR_TEXT_HIGHLIGHTCOLOR = 0xFFFFFFFF;

    public ViewPagerIndicator(Context context) {
        super(context);
    }

    public ViewPagerIndicator(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        screenW = getScreenWidth();

        // 获得自定义属性，tab的数量
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ViewPagerIndicator);
        mTabVisibleCount = a.getInt(R.styleable.ViewPagerIndicator_item_count, COUNT_DEFAULT_TAB);
        if (mTabVisibleCount < 0)
            mTabVisibleCount = COUNT_DEFAULT_TAB;
        a.recycle();

        // 初始化画笔
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setColor(Color.parseColor("#ffffffff"));
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setPathEffect(new CornerPathEffect(3));

    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        Log.v(TAG, "onFinishInflate: ");
        int cCount = getChildCount();
        if (cCount == 0)
            return;
        for (int i = 0; i < cCount; i++) {
            View view = getChildAt(i);
            LinearLayout.LayoutParams lp = (LayoutParams) view.getLayoutParams();
            lp.weight = 0;
            lp.width = screenW / mTabVisibleCount;
        }
        // 设置点击事件
        setItemClickEvent();
    }

    //设置点击事件
    public void setItemClickEvent() {
        int cCount = getChildCount();
        for (int i = 0; i < cCount; i++) {
            final int j = i;
            View view = getChildAt(i);
            view.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    mViewPager.setCurrentItem(j);
                }
            });
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mTriangleWidth = (int) (w / mTabVisibleCount * RADIO_TRIANGEL);// 1/6 of width
        mTriangleWidth = Math.min(DIMENSION_TRIANGEL_WIDTH, mTriangleWidth);
        // 初始化三角形
        initTriangle();

        // 初始时的偏移量
        mInitTranslationX = getWidth() / mTabVisibleCount / 2 - mTriangleWidth / 2;
    }

    /**
     * 初始化三角形指示器
     */
    private void initTriangle() {
        mPath = new Path();

        mTriangleHeight = (int) (mTriangleWidth / 2);// / Math.sqrt(2)
        mPath.moveTo(0, 0);
        mPath.lineTo(mTriangleWidth, 0);
        mPath.lineTo(mTriangleWidth / 2, -mTriangleHeight);
        mPath.close();
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        canvas.save();
        // 画笔平移到正确的位置
        canvas.translate(mInitTranslationX + mTranslationX, getHeight() + 1);
        canvas.drawPath(mPath, mPaint);
        canvas.restore();

        super.dispatchDraw(canvas);
    }

    /**
     * 设置关联的ViewPager
     */
    public void setViewPager(ViewPager mViewPager, int pos) {
        this.mViewPager = mViewPager;
        mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                // 设置字体颜色高亮
                resetTextViewColor();
                highLightTextView(position);

                // 回调
                if (onPageChangeListener != null) {
                    onPageChangeListener.onPageSelected(position);
                }
            }

            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                Log.i(TAG, "onPageScrolled: position=" + position + "  positionOffset=" + positionOffset);
                // 滚动
                scroll(position, positionOffset);

                // 回调
                if (onPageChangeListener != null) {
                    onPageChangeListener.onPageScrolled(position,
                            positionOffset, positionOffsetPixels);
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {
                // 回调
                if (onPageChangeListener != null) {
                    onPageChangeListener.onPageScrollStateChanged(state);
                }
            }
        });
        // 设置当前页
        mViewPager.setCurrentItem(pos);
        // 高亮
        highLightTextView(pos);
    }

    /**
     * 对外的ViewPager的回调接口
     */
    public interface PageChangeListener {
        public void onPageScrolled(int position, float positionOffset,
                                   int positionOffsetPixels);

        public void onPageSelected(int position);

        public void onPageScrollStateChanged(int state);
    }

    // 对外的ViewPager的回调接口
    private PageChangeListener onPageChangeListener;

    // 对外的ViewPager的回调接口的设置
    public void setOnPageChangeListener(PageChangeListener pageChangeListener) {
        this.onPageChangeListener = pageChangeListener;
    }

    /**
     * 高亮文本
     */
    protected void highLightTextView(int position) {
        View view = getChildAt(position);
        if (view instanceof TextView) {
            ((TextView) view).setTextColor(COLOR_TEXT_HIGHLIGHTCOLOR);
        }

    }

    /**
     * 重置文本颜色
     */
    private void resetTextViewColor() {
        for (int i = 0; i < getChildCount(); i++) {
            View view = getChildAt(i);
            if (view instanceof TextView) {
                ((TextView) view).setTextColor(COLOR_TEXT_NORMAL);
            }
        }
    }

    /**
     * 指示器跟随手指滚动，以及容器滚动
     *
     * @param position
     * @param offset
     */
    public void scroll(int position, float offset) {
        /**
         *  0-1:position=0 ;1-0:postion=0;
         */
        // 不断改变偏移量，invalidate
        mTranslationX = getWidth() / mTabVisibleCount * (position + offset);

        int tabWidth = getScreenWidth() / mTabVisibleCount;

        Log.i(TAG, "scroll: position=" + position + "  offset=" + offset);
        // 容器滚动，当移动到倒数最后一个的时候，开始滚动
        if (offset > 0 && position >= (mTabVisibleCount - 2) && getChildCount() > mTabVisibleCount && position < getChildCount() - 2) {
            if (mTabVisibleCount != 1) {
                this.scrollTo((position - (mTabVisibleCount - 2)) * tabWidth + (int) (tabWidth * offset), 0);
                Log.v(TAG, "scrollTo.x=" + ((position - (mTabVisibleCount - 2)) * tabWidth + (int) (tabWidth * offset)));
            } else {// 为count为1时 的特殊处理
                this.scrollTo(position * tabWidth + (int) (tabWidth * offset), 0);
                Log.v(TAG, "scrollTo.x=" + (position * tabWidth + (int) (tabWidth * offset)));
            }
        }
        invalidate();
    }

    /**
     * 设置可见的tab的数量
     *
     * @param count
     */
    public void setVisibleTabCount(int count) {
        this.mTabVisibleCount = count;
    }

    /**
     * 设置tab的标题内容 可选，可以自己在布局文件中写死
     *
     * @param datas
     */
    public void setTabItemTitles(List<String> datas) {
        // 如果传入的list有值，则移除布局文件中设置的view
        if (datas != null && datas.size() > 0) {
            this.removeAllViews();
            this.mTabTitles = datas;

            for (String title : mTabTitles) {
                // 添加view
                addView(generateTextView(title));
            }
            // 设置item的click事件
            setItemClickEvent();
        }
    }

    /**
     * 根据标题生成我们的TextView
     *
     * @param text
     * @return
     */
    private TextView generateTextView(String text) {
        TextView tv = new TextView(getContext());
        LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
        lp.width = getScreenWidth() / mTabVisibleCount;
        tv.setGravity(Gravity.CENTER);
        tv.setTextColor(COLOR_TEXT_NORMAL);
        tv.setText(text);
        tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);
        tv.setLayoutParams(lp);
        return tv;
    }

    /**
     * 获得屏幕的宽度
     *
     * @return
     */
    public int getScreenWidth() {
        WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics outMetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(outMetrics);
        return outMetrics.widthPixels;
    }
}
